Helical edge states in silicene and germanene nanorings in perpendicular magnetic field

Due to nonzero intrinsic spin-orbit interaction in buckled honeycomb crystal structures, silicene and germanene exhibit interesting topological properties, and are therefore candidates for the realization of the quantum spin Hall effect. We employ the Kane-Mele model to investigate the electron states in hexagonal silicene and germanene nanorings having either zigzag or armchair edges in the presence of a perpendicular magnetic field. We present results for the energy spectra as function of magnetic field, the electron density of the spin-up and spin-down states in the ring plane, and the calculation of the probability current density. The quantum spin Hall phase is found at the edges between the nontrivial topological phase in silicene and germanene and vacuum. We demonstrate that the helical edge states in zigzag silicene and germanene nanorings can be qualitatively well understood by means of classical magnetic moments. However, this is not the case for comparable-sized armchair nanorings, where the eigenfunctions spread throughout the ring. Finally, we note that the energy spectra of silicene and germanene nanorings are similar and that the differences between the two are mainly related to the difference in magnitude of the spin-orbit coupling.Comment: 17 pages, 10 figure

The development of resistance to tamoxifen in patients with breast cancer: our experience

Background: The study used data from medical and counselling of patients who were diagnosed with hormone-dependent breast cancer. Aim: The objective of the paper is to identify within a group of patients diagnosed with hormone sensitive breast cancer and those who have received adjuvant tamoxifen, and then to isolate the patients with whom the therapeutic effect of tamoxifen stopped (resistance to tamoxifen).Methods: The study analyzed 153 patients in the period from 2005 to 2011, at the Public Health Institution Hospital, Sveti Vračevi" in Bijeljina. Resistance to tamoxifen was developed by 60 patients (39.2%) and 93 patients (60.8%) did not develop resistance to it.Results: More common emergence of resistance is in the premenopausal group of patients (p<0.001). Statistically significant difference in frequency of resistance to tamoxifen was observed in the group of patients with ER-/PrR+ status of steroid receptors (p<0.001). In relation to HER-2 status of diagnosed cancer, a statistically significant difference in frequency of resistance emergence during tamoxifen therapy in patients with HER2-positive status (p<0.001) was observed. We found that there is a statistically significant difference between patients with metastatic in lymph nodes compared to patients who had no metastases in lymph nodes (X2=39.494; p<0.001).Conclusions: The analysis of menopausal status of patients, status of ER/PgR receptors status, HER-2 status of diagnosed cancer and status of lymph nodes trying to sort out the parameters on the basis of which a group of patients who can be expected to develop resistance to tamoxifen could be differentiated

The Effects of Different Doses of Sildenafil on Coronary Blood Flow and Oxidative Stress in Isolated Rat Hearts

The dose-response relationship of sildenafil effects on cardiac function is not completely elucidated. The aim of this study was to assess the effects of different doses of sildenafil on coronary flow and oxidative stress in isolated rat hearts. Coronary flow and markers of oxidative stress, including nitrite outflow, and superoxide anion production in coronary effluent, were determined for isolated rat hearts. The experiments were performed during control conditions and in the presence of sildenafil (10, 20, 50, 200 nM) alone or with Nω-nitro-L-arginine monomethyl ester (L-NAME) (30 μM). Sildenafil was shown to result in a significant increase in coronary flow at lower coronary perfusion pressure (CPP) values at all administered doses, whereas, with an increase in CPP, a reduction in coronary flow was observed. An increase in nitric oxide (NO) was most pronounced in the group treated with the lowest dose of sildenafil at the highest CPP value. After the inhibition of the NO-cyclic guanosine monophosphate (cGMP) signaling (NOS) system by L-NAME, only a dose of 200 nM sildenafil was high enough to overcome the inhibition and to boost release of O2−. That effect was CPP-dependent, with statistical significance reached at 80, 100 and 120 mmHg. Our findings indicate that sildenafil causes changes in heart vasculature in a dose-dependent manner, with a shift from a vasodilatation effect to vasoconstriction with a pressure increase. The highest dose administered is capable of producing superoxide anion radicals in terms of NOS system inhibition

Recommendations for customer engagement strategies

Customers are expected to play a fundamental role in the transition to a decarbonised and digitalised energy system. However, experience so far suggests that customer engagement in energy markets cannot be given for granted. This report investigates those barriers hindering customer engagement in flexibility markets and discusses strategies for their mitigation, aiming to unlock the untapped potential of the resources located at the customer’s premises and foster a more consumer-centric power system. Drawing from an extensive and multi-disciplinary literature review and benefiting from interactions with OneNet cluster demonstrators, this research identifies economic, behavioural, legal, and technical barriers to customer engagement in flexibility markets. Tailored recommendations are provided to surmount each of these barriers, advocating, among other things, for value stacking support, targeted awareness campaigns, regulatory adaptations, and robust infrastructure enhancements

Lipase catalyzed synthesis of flavor esters in non-aqueous media: Optimization of the yield of pentyl 2-methylpropanoate by statistical analysis

In this study, the synthesis of pentyl 2-methylpropanoate employing a commercial lipase from Candida rugosa was investigated, the emphasis being placed on analyzing the effects of various process conditions on the yield of ester. The response surface methodology (RSM) and five-level-five-factor central composite rotatable design (CCRD) were used to evaluate the effects of variables, namely the initial water content, 0.0–2.0 % (w/v), the reaction temperature, 35–75 °C, the enzyme concentration, 1.0–5.0 g dm-3, the acid/alcohol mole ratio, 1:2–5:2, and the reaction time, 4–48 h, on the yield (%) of ester. The production of pentyl 2-methylpropanoate was optimized and an ester yield response equation was obtained, enabling the prediction of ester yields from known values of the five main factors. It seems that the enzyme concentration, reaction time and acid/alcohol mole ratio predominantly determine the conversion process, while the amount of added water amount had no significant influence on the ester yield. Conversion of around 92 % of the substrate to ester could be realized using a concentration of lipase as low as 4.0 g dm-3 and in a relatively short time (26 h) at 35 °C, when a high substrate mole ratio of 2.5 was used

The development of resistance to tamoxifen in patients with breast cancer: our experience

Background: The study used data from medical and counselling of patients who were diagnosed with hormone-dependent breast cancer. Aim: The objective of the paper is to identify within a group of patients diagnosed with hormone sensitive breast cancer and those who have received adjuvant tamoxifen, and then to isolate the patients with whom the therapeutic effect of tamoxifen stopped (resistance to tamoxifen).Methods: The study analyzed 153 patients in the period from 2005 to 2011, at the Public Health Institution Hospital, Sveti Vračevi" in Bijeljina. Resistance to tamoxifen was developed by 60 patients (39.2%) and 93 patients (60.8%) did not develop resistance to it.Results: More common emergence of resistance is in the premenopausal group of patients (p&lt;0.001). Statistically significant difference in frequency of resistance to tamoxifen was observed in the group of patients with ER-/PrR+ status of steroid receptors (p&lt;0.001). In relation to HER-2 status of diagnosed cancer, a statistically significant difference in frequency of resistance emergence during tamoxifen therapy in patients with HER2-positive status (p&lt;0.001) was observed. We found that there is a statistically significant difference between patients with metastatic in lymph nodes compared to patients who had no metastases in lymph nodes (X2=39.494; p&lt;0.001).Conclusions: The analysis of menopausal status of patients, status of ER/PgR receptors status, HER-2 status of diagnosed cancer and status of lymph nodes trying to sort out the parameters on the basis of which a group of patients who can be expected to develop resistance to tamoxifen could be differentiated

Synthesis and characterization of zinc(II), palladium(II) and platinum(II) complex with 2-[1-(2-pyridinyl)ethylidene] oxamohydrazide. The crystal structure of bis{2-[1-(2-pyridinyl)ethylidene]oxamohydrazido}zinc(II) trihydrate

Complexes of Zn(II), Pd(II) and Pt(II) with 2-[1-(2-pyridinyl)ethylidene]oxamohydrazide (Hapsox) were synthesized and their structures were determined. All the complexes are of a neutral type with two apsox ligands coordinated to Zn(II) and one apsox ligand coordinated to Pd(II) or Pt(II). In each case, the polydentate was coordinated via pyridine and hydrazone nitrogens and a-oxyazine oxygen, forming an octahedral geometry around Zn(II), and a square planar one around Pd(II) and Pt(II). The structure determination was performed by IR, 1H-NMR and 13C-NMR spectroscopy, and for the Zn(II) complex by X-ray structure analysis

The Role of Macrophage Inhibitory Factor in TAA-Induced Liver Fibrosis in Mice: Modulatory Effects of Betaine

Macrophage inhibitory factor (MIF) is a multipotent cytokine, involved in the inflammatory response to infections or injuries. This study investigates the role of MIF in liver fibrosis and the modulating effect of betaine on MIF in thioacetamide (TAA)-induced liver fibrosis. The wild-type and knockout MIF−/− C57BL/6 mice were divided into the following groups: control; Bet group, which received betaine; MIF−/−; MIF−/−+Bet; TAA group, which received TAA; TAA+Bet; MIF−/−+TAA; and MIF−/−+TAA+Bet group. After eight weeks of treatment, liver tissue was collected for further analysis. The results revealed that TAA-treated MIF-deficient mice had elevated levels of hepatic TGF-β1 and PDGF-BB, as well as MMP-2, MMP-9, and TIMP-1 compared to TAA-treated wild-type mice. However, the administration of betaine to TAA-treated MIF-deficient mice reduced hepatic TGF-β1 and PDGF-BB levels and also the relative activities of MMP-2, MMP-9 and TIMP-1, albeit less effectively than in TAA-treated mice without MIF deficiency. Furthermore, the antifibrogenic effect of MIF was demonstrated by an increase in MMP2/TIMP1 and MMP9/TIMP1 ratios. The changes in the hepatic levels of fibrogenic factors were confirmed by a histological examination of liver tissue. Overall, the dual nature of MIF highlights its involvement in the progression of liver fibrosis. Its prooxidant and proinflammatory effects may exacerbate tissue damage and inflammation initially, but its antifibrogenic activity suggests a potential protective role against fibrosis development. The study showed that betaine modulates the antifibrogenic effects of MIF in TAA-induced liver fibrosis, by decreasing TGF-β1, PDGF-BB, MMP-2, MMP-9, TIMP-1, and the deposition of ECM (Coll1 and Coll3) in the liver